Characteristics of an inductance and a magnetic flux of a permanent magnet of a driving motor for a hybrid vehicle can be changed due to heat generated depending on an ambient temperature (e.g., engine room) and a driving condition. This has an influence on control characteristics (e.g., MTPA curve, weak field control, etc.) which can deteriorate torque control performance. Therefore, in order to optimize power performance and drivability of a hybrid vehicle, a method for compensating for a change in a torque depending on a change in a temperature of the driving motor is necessary.
A first conventional method for compensating for a change in a torque includes estimating a secondary resistance of a rotor for an induction motor, and then regenerating a current order through vector control calculation. A second conventional method for compensating for a change in a torque includes configuring n current control maps depending on a temperature and performing appropriate interpolation on current orders.
In the first conventional method, a control target motor is the induction motor, and a secondary resistance value of the rotor depending on a change in a temperature is estimated to generate the current orders. On the other hand, in the second conventional method, after the n current control maps depending on the temperature of a motor are configured, interpolation is performed on current orders at two reference temperatures close to an actual temperature of the motor at the time of applying a torque order to generate current orders in a current orderer.
That is, the second conventional method, it is necessary to configure the n current control maps depending on the temperature in order to implement a control scheme. It is also necessary to apply all of the current orders that may be combined with each other using a microcontroller unit (MCU) in all driving regions to measure a measured torque, and then calculate a maximum torque per ampere (MTPA) curve and a weak field control curve in order to configure one current control map.
However, it takes significant time and effort to configure the n current control maps by repeating the above-mentioned process n times.